1. Field of the Invention
The present invention relates to an image processing apparatus and an image processing method, and more particularly, to an image processing apparatus and an image processing method which can perform a process using a detection result of a face image region.
2. Description of the Related Art
In the related art, there has been proposed a technique in which an edge in which the change of a pixel value is sharp is kept without change, the part other than the edge is smoothed, and an amplitude component obtained by subtracting a smoothed component from an input signal is amplified, so as to independently perform an image process for components which do not include the edge (refer to Japanese Unexamined Patent Application Publication No. 2001-298621, for example).
FIG. 22 illustrates a configuration example of an image processing apparatus 200 corresponding to an image processing apparatus as disclosed in Japanese Unexamined Patent Application Publication No. 2001-298621. This image processing apparatus 200 includes a non-linear filter 201, a subtractor 202, an addition-subtraction amplifier 203, and an adder 204.
An input image data Vin is supplied to the non-linear filter 201. The non-linear filter 201 is configured, for example, using an ε (epsilon) filter. In the non-linear filter 201, the input image data Vin is smoothed while keeping an edge, and a structure component ST1 which is smoothed data is generated. Further, the input image data Vin is supplied to the subtractor 202. The structure component ST1 generated in the non-linear filter 201 is also supplied to the subtractor 202. In the subtractor 202, the structure component ST1 is subtracted from the input image data Vin, and a texture component TX1 is obtained as output data.
The texture component TX1 obtained in the subtractor 202 is supplied to the addition-subtraction amplifier 203. In the addition-subtraction amplifier 203, the texture component TX1 is amplified to obtain a texture component TX2. The gain of the addition-subtraction amplifier 203 is adjusted by a user manipulation, for example. The texture component TX2 obtained in the addition-subtraction amplifier 203 is supplied to the adder 204. To the adder 204 is also supplied the structure component ST1 generated in the non-linear filter 201. In the adder 204, the texture component TX2 is added to the structure component ST1 to obtain output image data Vout.
In the image processing apparatus 200 shown in FIG. 22, the output image data Vout in which low amplitude components other than the edge component are emphasized is obtained while keeping the edge component of the input image data Vin. For this reason, it is possible to enhance the texture without damaging the sharpness of the entire screen. However, in this image processing apparatus 200, since the gain of the addition-subtraction amplifier 203 is indiscriminate over the entire screen, the emphasis may be excessive for a face image to thereby induce a feeling of strangeness in the image.
Thus, in the related art, there has been proposed a technique which detects a skin color region and performs control so as to suppress the emphasis level in the skin color region compared with other regions to obtain an appropriate texture (refer to Japanese Unexamined Patent Application Publication No. 2003-348615, for example).
FIG. 23 illustrates a configuration example of an image processing apparatus 200A corresponding to an image processing apparatus as disclosed in Japanese Unexamined Patent Application Publication No. 2003-348615. This image processing apparatus 200A includes a skin-chromaticity detector 205 and a gain controller 206, in addition to a non-linear filter 201, a subtractor 202, an addition-subtraction amplifier 203 and an adder 204.
The sections of the non-linear filter 201, the subtractor 202, the addition-subtraction amplifier 203 and the adder 204 of image processing apparatus 200A are the same as in the image processing apparatus 200 as shown in FIG. 22, and thus, detailed description thereof will be omitted.
An input image data Vin is supplied to the skin-chromaticity detector 205. In the skin-chromaticity detector 205, the skin-chromaticity is detected for every pixel on the basis of the input image data Vin. The value of the skin-chromaticity is the maximum for a predetermined skin color and decrease with increasing departure from the predetermined skin color. The skin-chromaticity detected in the skin-chromaticity detector 205 in this way is supplied to the gain controller 206. In the gain controller 206, a gain control signal CN1 corresponding to the skin-chromaticity is obtained in the correspondence relation as shown in FIG. 24, for example.
The gain control signal CN1 obtained in the gain controller 206 is supplied to the addition-subtraction amplifier 203. In this case, the gain of the addition-subtraction amplifier 203 becomes a value proportional to the level of the gain control signal CN1. For this reason, the gain of the addition-subtraction amplifier 203 is suppressed in an image region where the skin-chromaticity is high. Accordingly, the emphasis level is suppressed in a face image region compared with other regions to thereby obtain an appropriate texture.